Transmitter optical sub-assembly structure and active alignment method thereof

Abstract

Structures and active alignment methods thereof of a Transmitter Optical Sub-Assembly (TOSA) Structure are provided, that includes a light source sub-assembly including a light source component assembled on a light source bench; an optical sub-assembly including an optical component assembled on an optical bench; and a silicon chip including a coupler. A light emitted by the light source component is received by the coupler via the optical component along an optical path, the light source bench and the optical bench are thermally conductive to dissipate heat. The light source sub-assembly and the optical sub-assembly are actively aligned at the same time to optimize optical coupling between the light source sub-assembly and the optical sub-assembly by optimizing positions and a distance of the light source sub-assembly and the optical sub-assembly, the positions and the distance are flexibly adjusted during the active alignment process.

What is claimed is: 
     
       1. A transmitter optical sub-assembly structure, comprising:
 a light source sub-assembly comprising a light source bench, a laser diode, and a laser diode lens positioned downstream of the laser diode along an optical path,
 wherein the laser diode and the laser diode lens are assembled on the light source bench; and 
 
 an optical sub-assembly comprising an optical bench, an isolator, and a prism positioned downstream of the isolator along the optical path,
 wherein the isolator and the prism are assembled on the optical bench; and 
 
 a silicon chip comprising a coupler,
 wherein a light emitted by the laser diode is received by the coupler via the isolator along the optical path, 
 wherein the light source bench and the optical bench are thermally conductive to dissipate, individually or together, heat generated from the laser diode, 
 wherein the light source bench and the optical bench are disposed adjacent to each other along a same axis, 
 wherein the light source sub-assembly, as a whole sub-assembly, and the optical sub-assembly, as another whole sub-assembly, are aligned to optimize optical coupling between the light source sub-assembly and the optical sub-assembly by optimizing positions of the light source sub-assembly and the optical sub-assembly, and a distance between the light source sub-assembly and the optical sub-assembly with respect to each other, 
 wherein the laser diode lens of the light source sub-assembly is configured to be located between the laser diode of the light source sub-assembly and the isolator of the optical sub-assembly, 
 wherein the positions of the light source sub-assembly and the optical sub-assembly, and the distance between the light source sub-assembly and the optical sub-assembly, are adjusted by lighting the laser diode and monitoring optical output power received by the optical bench, 
 wherein the positions of the light source sub-assembly and the optical sub-assembly, and the distance between the light source sub-assembly and the optical sub-assembly are configured for maximal optical output power, and 
 wherein a distance between the laser diode and the laser diode lens stays the same during the alignment. 
 
 
     
     
       2. The transmitter optical sub-assembly structure of  claim 1 , wherein the light source sub-assembly and the optical sub-assembly are both positioned beside the silicon chip. 
     
     
       3. The transmitter optical sub-assembly structure of  claim 2 , wherein the light source sub-assembly, the optical sub-assembly, and the silicon chip are all assembled on an electrical substrate. 
     
     
       4. The transmitter optical sub-assembly structure of  claim 1 , wherein the light source sub-assembly and the optical sub-assembly are both assembled on the silicon chip. 
     
     
       5. The transmitter optical sub-assembly structure of  claim 1 , wherein the optical sub-assembly is assembled on the silicon chip, and the light source sub-assembly is assembled on an electrical substrate that is positioned beside the silicon chip. 
     
     
       6. The transmitter optical sub-assembly structure of  claim 1 , wherein the optical sub-assembly is assembled on the silicon chip, and
 wherein the silicon chip and the light source sub-assembly are assembled on an electrical substrate. 
 
     
     
       7. The transmitter optical sub-assembly structure of  claim 6 , wherein the silicon chip is assembled in a cavity of the electrical substrate. 
     
     
       8. The transmitter optical sub-assembly structure of  claim 6 , wherein the silicon chip is assembled on a step of the electrical substrate. 
     
     
       9. A transmitter optical sub-assembly structure, comprising:
 a light source sub-assembly comprising a light source bench, a laser diode, and a laser diode lens positioned downstream of the laser diode along an optical path,
 wherein the laser diode and the laser diode lens are assembled on the light source bench; 
 
 an optical sub-assembly comprising an optical bench; and 
 a silicon chip comprising a coupler, and supporting at least one of the light source sub-assembly and the optical sub-assembly,
 wherein the light source bench and the optical bench are thermally conductive to dissipate, individually or together, heat generated from the laser diode, 
 wherein the light source bench and the optical bench are disposed adjacent to each other, 
 wherein the light source sub-assembly, as a whole sub-assembly, and the optical sub-assembly, as another whole subassembly, are aligned with the laser diode lens of the light source sub-assembly located between the laser diode of the light source sub-assembly and the optical sub-assembly, to optimize optical coupling between the light source sub-assembly and the optical sub-assembly, 
 wherein positions of the light source sub-assembly and the optical sub-assembly, and a distance between the light source sub-assembly and the optical sub-assembly, are configured for maximal optical output power, and 
 wherein a distance between the laser diode and the laser diode lens stays the same during the alignment. 
 
 
     
     
       10. The transmitter optical sub-assembly structure of  claim 9 , wherein the optical sub-assembly further comprises an isolator and a prism positioned downstream of the isolator along the optical path,
 wherein the isolator and the prism are assembled on the optical bench. 
 
     
     
       11. The transmitter optical sub-assembly structure of  claim 9 , wherein the silicon chip supports the light source sub-assembly and the optical sub-assembly. 
     
     
       12. The transmitter optical sub-assembly structure of  claim 9 , further comprising:
 an electrical substrate that supports the silicon chip. 
 
     
     
       13. The transmitter optical sub-assembly structure of  claim 12 , wherein the silicon chip is located in a cavity or on a step of the electrical substrate. 
     
     
       14. The transmitter optical sub-assembly structure of  claim 1 , wherein the coupler is a grating coupler or an edge coupler, and
 wherein the grating coupler is associated with off-plane coupling and the edge coupler is associated with in-plane coupling. 
 
     
     
       15. A method, comprising:
 forming a light source sub-assembly comprising a light source bench, a laser diode, and a laser diode lens positioned downstream of the laser diode along an optical path,
 wherein the laser diode and the laser diode lens are assembled on the light source bench; and 
 
 forming an optical sub-assembly comprising an optical bench, an isolator, and a prism positioned downstream of the isolator along the optical path,
 wherein the isolator and the prism are assembled on the optical bench; and 
 
 a silicon chip comprising a coupler,
 wherein a light emitted by the laser diode is received by the coupler via the isolator along the optical path, 
 wherein the light source bench and the optical bench are thermally conductive to dissipate, individually or together, heat generated from the laser diode, and 
 wherein the light source bench and the optical bench are disposed adjacent to each other along a same axis, 
 
 aligning the light source sub-assembly, as a whole sub-assembly, and the optical sub-assembly, as another whole sub-assembly, to optimize optical coupling between the light source sub-assembly and the optical sub-assembly by optimizing positions of the light source sub-assembly and the optical sub-assembly, and a distance between the light source sub-assembly and the optical sub-assembly with respect to each other,
 wherein the laser diode lens of the light source sub-assembly is located between the laser diode of the light source sub-assembly and the isolator of the optical sub-assembly, 
 wherein the positions of the light source sub-assembly and the optical sub-assembly, and the distance between the light source sub-assembly and the optical sub-assembly, are adjusted by lighting the laser diode and monitoring optical output power received by the optical bench, 
 wherein the positions of the light source sub-assembly and the optical sub-assembly, and the distance between the light source sub-assembly and the optical sub-assembly, are configured for maximal optical output power, and 
 wherein a distance between the laser diode and the laser diode lens stays the same during the alignment. 
 
 
     
     
       16. The method of  claim 15 , wherein a position of the light source sub-assembly is adjusted as a whole unit, and a position of the optical sub-assembly is adjusted as another whole unit during the alignment. 
     
     
       17. The method of  claim 15 , wherein the light source sub-assembly and the optical sub-assembly are both positioned beside the silicon chip. 
     
     
       18. The method of  claim 17 , wherein the light source sub-assembly, the optical sub-assembly, and the silicon chip are all assembled on an electrical substrate. 
     
     
       19. The method of  claim 15 , wherein the light source sub-assembly and the optical sub-assembly are both positioned above the silicon chip. 
     
     
       20. The method of  claim 15 , wherein the optical sub-assembly is assembled on the silicon chip, and the light source sub-assembly is assembled on an electrical substrate that is positioned beside the silicon chip.